Electric forging



1938- G. DQM. BENEDETTO 2,127,625

ELECTRIC FORGING Filed July 14, 1957 Patented Aug. 23, 1938 UNITED STATES PATENT OFFICE ELECTRIG FORGIN G Giuseppe Domenico Mario Benedetto, Barnes, London, England Application July 14, 1937, Serial No. 153,594 In Great Britain July 29, 1936 4 Claims. (01. 219-3) This invention comprises improvements in or is applied in the direction of the arrow I! upon relating to electric forging. It sometimes hapthe end of the composite workpiece by the usual pens that it is desirable to produce forgings which feeding ram of the upsetting machine to cause have certain physical properties in one part and the work to slide through the vice jaws l4, l5 and different physical properties in another part. For thus to feed fresh metal continuously into the 5 example, the rear axle shafts of motor vehicles upset head, which gradually assumes the form have hitherto been in general made in two porshown by the broken line l8. Upsetting is contions, namely the shaft proper, of high tensile tinued until the high tensile shank l3 has been alloy steel and the hub portion of cheaper matefed into the head l8 and expanded to the form l rial such as steel castings, the two portions beindicated by the broken line I9. It is possible 10 ing united together by tapered splines and a fasin some instances merely to abut the length of tening nut. More recently it has been found the material II and I3 firmly together, or screw possible to produce the whole in a single piece them together, the heat produced at the juncby upsetting a large head on the end of the high tion when this passes through into the space bei tensile steel shaft in an electric forging machine, tween the electrodes being sufficient (augmented but while this permits elimination of much matemporarily by increasing the current if neceschining and the nut and screwed end of the sary) to make sure that the parts are welded to shaft for holding the parts together, it involves one another. It is, however, preferred that they utilization of high tensile steel for relatively low should be welded first before being upset.

) stresses which are encountered in the hub as well The forging, after being removed from. the upas for the more highly stressed shaft portion. set machine is shown at Figure 2. While the T e presen invention o p es a pr of head is still hot it is placed in a die-press and forging characterized by feeding w lengths of brought to final shape as indicated in Figure 3, distinct metals successively into an upset head which shows an axle shaft forging for automo- 5 in an electr psetting machine so that the secbile work. It will be observed that owing to the 0nd len th beco es p at d in t ead in high tensile stem l3 having been forced into the union with the first. upset head l8 and spread out therein, as illus- The tWO lengths o metal ay b preliminarily trated in Figures 1 and 2, when the die-pressing un th for example y W n prior to operation is effected, the high tensile material is feeding them into the upset head. spread out within the hub l8 and the area of The forg n a e the Composite upset head the junction line between the high tensile mahas been formed, may be die-pressed in Such terial l3 and the low tensile steel [8 which forms manner as to extend the area 0f junction bethe bulk of the hub is expanded as indicated at tween the two metals. 2%], as well as being subjected to a high compres- F0110Wirlg is a description, by Way O ex p sion pressure in the die, thus ensuring perfect of one set of operations carried out in accordance cohesion and uniformity between the two por- W t t process 0 the present ihVehtiOrltions of the forging and also the effective dis- In the accompanying drawing:- tribution of stresses from the axle shaft portion Figure 1 is a diagrammatic View of a forging [3 i t th hub tion [8,

) Operation in an upsetting machine; It is found that the joint between the two steels g e 2 ShOWS & forging after being upset, and preserves its cohesion during the upsetting op- Figure 3 ShOWS the Same after being (116- eration and that the expanded area of this joint, pressed. due to the upsetting operation, leads to the pro- Referring to Figure 1, a length of carbon steel duction of a forging which is in every respect as 3 II is electrically welded at l2 to a length of high coherent as if it had been made of one unitary tensile steel l3. The composite bar is gripped piece of metal while the quantity of high tensile between the upper member l4 and the lower steel required for the production of the forging member 15 of the vice of an electric upsetting is reduced to approximately one half, thus showmachine and the end of the bar pressed against ing a very considerable saving in the cost of the J the anvil 16. The vice and the anvil are conpiece. If the relative lengths of the carbon steel nected in well known manner to the secondary and the high tensile alloy steel are appropriately terminals of an electric step-down heating transchosen a sufiicient amount of the alloy steel will former, which brings the metal between the vice enter the forged head to spread radially on the and the anvil up to forging temperature by the shaft side of the head to such a distance as to heating effect of the electric current. Pressure adequately and suitably distribute the stresses from the highly stressed axle shaft portion into the head and the carbon steel is therefore relieved of undue stress at its centre which is not the case where it is connected to the shaft by splines.

I claim:

1. A process of forging characterized by feeding two lengths of distinct metals successively into an upset head in an electric upsetting machine so that the second length becomes incorporated in the head in union with the first with an enlarged area of junction and thereafter diepressing the composite upset head in such manner as to extend further the area of junction between the two metals.

2. A process of forging comprising in combination the steps of first uniting two lengths of metal to one another end to end and then feeding the united lengths successively into an upset head in an electric upsetting machine so that the second length becomes incorporated in the head in union with the first with an enlarged area of junction and thereafter die-pressing the composite upset head in such manner as to extend further the area of junction between the two metals.

3. A process of forging comprising in combination the steps of uniting a length of high tensile steel alloy to a length of relatively low tensile steel and thereafter feeding the united lengths into a composite head in an electric upsetting machine, the low tensile length of material being forced first to enter the upset head and form the bulk thereof, while a portion of the high tensile steel is also fed into the head sub sequently so as to become incorporated in the head in union with the low tensile portion with an enlarged area of junction and thereafter diepressing the composite upset head in such manner as to extend further the area of junction between the two metals.

4. A process of forging axle shafts for motor vehicles comprising in combination the steps of welding together a length of high tensile axle steel and a length of relatively low tensile steel, feeding the united lengths successively into an upset head in an electric upsetting machine in such manner that the low tensile steel forms the bulk of the head and the high tensile steel is fed subsequently thereinto so as to become partially incorporated in the head with an enlarged area of junction and thereafter die-pressing the head portion so that the high tensile steel has a still further enlarged convex junction with the low tension steel and the two together constitute an axle hub.

GIUSEPPE DOMENICO MARIO BENEDETTO 

